Artillery projectiles are conventionally loaded with cast explosives by pouring the liquid explosive composition into the projectile shell through a funnel inserted into the threaded opening in the nose of the shell, and allowing the explosive composition to cool or cure to a solid cast. After removal of the funnel, a cavity is drilled in the cast and a threaded, metal fuzewell liner for containing a fuze or supplementary charge for detonating the explosive is inserted into the cavity, and then threadedly secured to the shell at said opening.
Tests have shown that the probability of dangerous premature explosions in the gun barrel, i.e. explosive initiation by setback pressures and shock in high explosive loaded artillery projectiles, is substantially increased by the presence of separation between the base of the shell and the explosive cast. Much effort has been directed to minimizing such base separation during loading operations due to contraction of the cast on cooling and solidification. At present, most projectiles are post-heated in an attempt to minimize such base separation. During the post heating operation, the explosive charge, e.g. TNT and Composition B, is heated and then cooled, whereby the volume of the cast in the projectile can be increased by a small, limited amount. This expensive procedure is repeated up to three recycle operations in an attempt to meet the maximum allowable base separation, which if not achieved requires that the projectile must be suitably reworked, which is costly, since it is unfit for field use. While this procedure does not eliminate base separation entirely, it has enabled most lots of projectiles to meet specification requirements.